Co-pending application, Ser. No. 581,085; now U.S. Pat. No. 4,674,834 of George D. Margolin, filed Feb. 17, 1984, and assigned to the assignee of the present application, discloses an initializing technique for making a noncoherent optical fiber bundle "coherent" electronically. The initializing technique called for moving a light beam, having a dimension small compared to the size of a fiber, along a path which intersects the fiber ends in the entrance field. An optical sensor array is abutted against the exit field and interrogated each time the light beam is moved to determine which sensors of the sensor array are illuminated each time the beam is moved. In this manner, the light beam merely needs to be moved in increments rather than being required to be moved to predetermined positions in the entrance field.
The sensor array includes many sensors (i.e. 65,000) compared to the number of fibers. Consequently, each fiber overlies more than ten sensors. A procedure is described for choosing a single unique sensor for each end in the exit plane.
Co-pending application, Ser. No. 894,792, filed Aug. 8, 1986, also for George D. Margolin and assigned to the assignee of the present application discloses an initializing procedure which records the position of each sensor first activated each time a beam, in the form of a narrow slit of light, is moved. A computer stores the addresses of the activated sensors until the beam reaches a point along the path where a sensor is no longer activated. For each position of the beam, all the activated ssensors are plotted. The number of activated sensors is compared for several sequential positions of the beam. A maximum in the number ofactivated sensors for such a sequence of positions and a selected sensor in that maximum is taken as the position of the corresponding fiber end in the exit field to the position of the light beam.
There are two caveats to this procedure. The first is that the fibers in the exit field are in random positions. Thus, for each position of a beam, sensors may be activated in several areas of the sensor array. This is because the beam may be in a position to send light through more than one fiber when the sensor array is interrogated. Thus, the maximum which is sought above, is a maximum in the number of activated sensors in one area of the sensor array.
The second caveat is that the fibers in the entrance field are not organized in predetermined positions. That is to say, the exact positions of a particular fiber in the entrance field is not known. Even for an ideally linear entrance field, some fibers may be offset laterally from the axis of the field. Others may be touching one another while still others are spaced apart in non-uniform distances. Still others may be bunched together. It is not necessary to move the beam to exact predetermined positions for each fiber. That would be a very time-consuming and expensive procedure. It is only necessary to move the beam incrementally along a path and to interrogate the sensor array in the manner described above.
The foregoing initializing procedure requires the computer to make several computations after each interrogation of the sensor array. Such computations require time for each position of the beam. For fiber optic array of interest there are thousands of fibers. Thus, the amount of time required for initializing an array is relatively high. Although the cost of initializing is low, still for low cost scanner applications particularly, a faster initializing procedure would be very attractive.